In the wake of a 7.7 magnitude quake off the Canadian coast, a small tsunami has been detected in Hawaii.
A tsunami generated by a powerful earthquake in Canada hit the US state of Hawaii late Saturday, an official from the Pacific Tsunami Warning Center said.
"The tsunami is arriving right now," Gerard Fryer, a senior geophysicist with the center, told reporters. "It is coming in as we speak."
Television images from the island of Oahu showed relatively small waves peacefully rolling toward the shore.
But Fryer urged Hawaii residents not to deceived by appearances.
"Typically, the first wave is not the largest," he said, adding that subsequent waves could be much larger, resulting in flooding in low-lying areas.
"If the waves are big, the all-clear may take six or seven hours," Fryer said.
The expected arrival time of the tsunami was 10:28 pm local time Saturday (0828 GMT Sunday).
The alert came after a major 7.7 magnitude earthquake shook the Queen Charlotte Islands off the west coast of Canada late Saturday.
The epicenter of the tremor, which occurred at 8:04 pm (0304 GMT Sunday) was located 139 kilometers (86 miles) south of the town of Masset, the US Geological Survey said.
Numerous aftershocks, some as large as magnitude 4.6, followed the initial quake, Canadian officials reported.
The regional West Coast-Alaska Tsunami Warning Center also issued a regional warning for coasts located near the epicenter of the earthquake.
Emergency officials in British Columbia said a small tsunami had been recorded on a deep ocean pressure sensor, but its effect was not immediately known.
The officials urged residents in low-lying coastal areas to be alert to instructions from local officials and be prepared to move to higher ground.
"The tsunami alarm went off and everybody went to the evacuation site," Danny Escott, owner of the Escott Sportfishing lodge near Massett, told AFP by telephone.
Natural Resources Canada said in a statement that the temblor was felt across much of north-central British Columbia, including Haida Gwaii as the Queen Charlotte Islands are otherwise called, Prince Rupert, Quesnel, and Houston.
"There have been no reports of damage at this time," the ministry added.
However, experts said tremors exceeding magnitude 7.0 were extremely dangerous.
"A 7.7 is a big, hefty earthquake. It's not something you can ignore," Gerard Fryer, senior geophysicist at the Pacific Tsunami Warning Center told CNN International.
He explained that the latest tremor had occurred partly under an island, but mostly under shallow water.
"I think we have to be thankful it happened where it did," Fryer said. "If that were a heavily populated area, it would have caused significant damage."
"It definitely would have done significant damage if it had been under a city," the geophysicist added.
The Globe and Mail newspaper reported that the US Coast Guard in Alaska was trying to warn everyone with a boat on the water to prepare for a potential tsunami, the report said.
The Canadian paper also quoted Lieutenant Bernard Auth of the Juneau Command Center as saying that the US Coast Guard was working with local authorities to alert people in coastal towns to take precautions.
The earthquake reading was based on the open-ended Moment Magnitude scale used by US seismologists, which measures the area of the fault that ruptured and the total energy released.
The Queen Charlotte Islands, which are also known by their official indigenous name of Haida Gwaii, comprise about 150 islands located north of Canada's Vancouver Island. Their total population is about 5,000. The Haida people make up about 45 percent of the total population.